Internal combustion engine



Sept. 27, 1932.

W. H. ROBERTSON INTERNAL coMBUsTIoN ENGINE Original Filed Dec. 13, 19194 sheets-sheet 1 Sept. 27, 1932.

w. H. ROBERTSON- INTERNAL coniBUsTIoN ENGINE 4 SheetS-Sheef 2 Original'Filed Dec. 13, 1919 IN VENT 0R v SePf- 27, 1932- w. H. ROBERTSON1,879,911

. j INTERNAL coNBUsTIoN ENGINE original F11-ed Dec. 13, 1919 4sheets-sheet s gir i l N V [."N T 0R WILL/19N H. ROBERT'M Sept. 27;1932. w. H. RoBER-rsoN l 1,879,911

INTERNAL COMBUSTION lENGINE? origina1`Fi1ed Dec. 13, 1919 4 sheets-sheet4` Patented Sept. 27, 1932 4UNITED, STATES PATENT OFFICE WILLIAM n.ROBERTSON, or nAYroiv, onro,

INTERNAL COMBUSTION ENGINE Original application illed December 13, 1919,Serial No. 844,715. Divided sind this November 26, 1.928.

This invention relates to internal combustion engines, and moreespecially to two cycle engines of the Diesel type.

One aim of the invention is to providean engine having the highestpossible thermal eliiciency, and, in carrying out this aim, novel meansare provided for securing an intimate mixture of the air for supportingcombustion and the fuel separately injected into the cylinder; novelmeans areprovided for scavenging the engine in the most eifectivemanner; an

novel means are provided for utilizing the' energy of the exhaust gas.

I aim tosecure high thermal eiciency by providing that the air used tosupport combustion shall be initially compressed by the operation of theengine and that it shall be caused to swirl through the engine cylinderin order more t-h roughly to mix with the'injected fuel. The'air whichenters the cylinder after the 'explosion has taken place is likewisecaused to rotate as it passes through the cylinder so that, by itsswirling action, this air willeifectively scavenge the cylinder.

In order to utilize the energy of the exhaust gas, I provide that theexhaust shall pass through a turbine, preferably ofthe high speedsinglle stage type, before passing into the atmosphere.

Another obj ect of the -invention is t0 secure as perfect a dynamicbalance as possible. One manner of accomplishing this result is toprovide Vtwo oppositely reciprocating pistons in the cylinder, saidpistons cooperating. with oppositely revolving crank shafts whichoperate oppositely revolving lywheel's. By making the moving parts ofequal weight, the vibration which oneset of parts would tend to set upis offset by the equal and opposite eifect of the other set of partswhich operates contrarywise.

A further object is to reduce to a minimum the weight of the engine perhorsepower. This object lis accomplished in one manner L by utilizingflywheels of comparatively small mass and gearing them up to the enginecrank shafts so that the flywheel elements, by their increased speed,will be effective to produce a steadv flow of power from the engine. Y.

In this connection itis a further object that application illed SerialNo. 321,843. f

the moving element of the engine operated air compressor shall act asone flywheel ele- Another obJect of the invention isto provide novelmeans for injecting fuel into the engine in such av manner as to bethoroughly mixed with the combustion air to insure av uniform fuelmixture.

A further object is to provide a valvelessv well as the .weight fuelpump for injecting fuel into the engine.

A further object is to dprovide for the control-of the en 'ne spee bycontrolling the operation of t e pump by the engine. One manner ofaccomplishing this object is to control the amount of fuel forced intothe engine cylinder during each cycle of the englne operation. c f

A further ob'ect is to eliminate noise by providing a mulller ofimproved construction which will relieve the exhaust of a large portionof its energy while permitting a. rapid escapeinto the outsideatmosphere. In car.- rying out this object I provide that theexhaustturbine shall act also as the muler. In accomplishing this object, the,number of engine parts and the weight per horespower are reduced.

'Other' and further objects and advantages of the present invention willbe apparent from the following description of a preferred embodimentthereof, reference being made to the accompanying drawings.

In the drawings l Fig. 1 is a side elevation of an engine embodying thepresent invention;

' Fig. 2 1s a sectional view taken on line 2-2 of Fig. 1;

Fig. 3, Fig. 4 and Fi 5 are sectional views taken on line 3-3 of ig. 2showingthe-en-L gine parts in their relative positions during differentstages of the engine cycle;

Fig. 6 is a left end elevation of the fuel pump and operating mechanism;

Fig., 7 is a sectional view t ken on line 7-7 of Fig, 6;

tional views, showing three different stages of operation of the pumpwhen set to deliver i a rzlatively large amount of fuel per engine cyce;

Fig. '12, Fig. 13, Fig. 14 and Fig. 15 are similar sectional viewssimilar to those shown in Fig. 7, Fig. 9, Fig. and Fig. 11 showing -fourdifferent stages of pump operation when the pump is set to deliver arelatively small quantity of fuel per engine cycle;

Fig. 16 is a sectional view taken on line 16-16 of Fig. 2;

Fig. 17 is a sectional vicw taken on line 17-17 of Fig. 2;

Fig. 18 is a sectional view taken on line 18-18 of Fig. 1;

Fig. 19 is' a sectional vview taken on line 19-19 of Fig. 1;

Fig. 20 is an end elevation of the fuel nozzle; and

Fig. 21 is a sectional view taken on line 21-21 of Fig. 20.

Referring to the drawings, a basesupports crank cases 31 and 32, whichsupport between them a cylinder 33 in which slide pistons l34 and 35.Piston 34 is connected by rod 36 with crank 37 formed preferablyintegrally with crank shaft 38. Piston yis connected by rod 39 withcrank 40 also formed integrally with crank shaft 41.

Shaft 38 directly drives gear 42, fuel pump cam 43, and planetary geararm 44; while turbine rotor 45 is mounted to rotate thereon. Shaft 41directly drives gear 46, slide valve cams 47 48, and planetary gear arm49, while fan rotor 50 is mounted to rotate thereupon.

A turbine, housing 51 mounted upon crank case 31 is divided by -apartition 52into a turbine gear case 53 and a turbine rotor case 54. Theend wall of housing 51 is provided with apertures 55 and with inwardlyprojecting ledges 56 and 57, see Fig. 16; and the cylindrical wall ofhousing 51 is provided with internal gear 58, which meshes withplanetary gears 59 and 60, rotatably mounted on gear arm 44. Housing 51is'pro'vided with holes 55a, see Fig. 16. Gears 59 and 60 mesh'with'pinion 61 attached to bearing ,sleeve 62 which supports turbine rotor45 which rotates normally in the direction of arrow 45a.

Rotor 45 is provided with blades 63 arranged to be impinged upon by theexhaust gases which enter through exhaust pipe 64 and circulate throughthe rotor 45 and into rotor case 54 as indicated approximately by arrows65. The ledge 56 divides the spent gases into .two streams which tend tomeet against the ledge 57, this ledge 57 serving to divert the spentgases out through holes 55. Any part of the exhaust carried around bythe rotor blades may escape through openings 55a. y

Exhaust pipe 64 is connected with annular exhaust passage of cylinder33, and passage 70 is connected with cylinder 33 through exhaust ports71.

A fan housing is provided with a fan rotor case 81 provided with acentral aperture 82 communicating with fan gear case 83, which in turnis connected with the interior of crank case 32 through holes 84.Housing 8O is provided with an internal gear 85, see Fig. 2 and Fig. 17,which meshes with planetary gears 86 and 87, rotatably mounted upon geararm 49.v Gears 86 and 87 meshwith pinion 88 which is directly connectedwith iti fan rot-or 50'. The normal direction of rotation of the gearingis indicated in Fig. 17 by arrows 49A, 86A and 88A.

Fan casing 81 is connected by air intake pipe 90 with annular intakechamber l91, see Figs. 2 and 19. Communication between chamber 91 andcylinder 33 is controlled by slide valve 92, provided with ports 93.l

Crank case 32 supports a rod 94, see Figs. 2 and 3, which supports bellcrank levers 95, 96 carrying cam rollers 97, 98 respectively,cooperating with races provided with cams 47, 48 respectively. Rollers97, 98 are connected with arms 99, 100 respectively of the valve 92.Levers 95, 96 cooperate with counterbalance levers 101, 102respectively,

mounted upon rod 103 carried by crank case 32.

` Crank cases 31 and 32 are provided with air inlet ports 111 and 112,respectively, closed by spring pressed valves 113 and 114, respectively,which are arranged to be opened by suction within the crank cases duringthe compression stroke of Ithe pistons. Crank cases 31 and 32 areconnected by pipe 115.

Referring to Figs. 6 to 8 inclusive, the fuel pump will next bedescribed. Pump cam 43 is provided with races120-and 121 cooperatingwith rollers 122 and 123, respecrtively, carried by levers 124 and 125respectively. Levers 124 and 125 are connected by studs 126 and 127,respectively, with plungers 128 and 129, respectively, which slidewithin sleeve 130 mounted in pump frame l131 formed preferablyintegrally with a sidewall of crank case 31. Frame 131 is provided withfuel inlet passage 132 connected with inlet pipe 133 which leads fromafuel tank, not shown. Passage 132 leads into inlet port 134 provided inVsleeve 130. F rame 131 is provided with fuel outlet passage 135connected with fuel outlet pipe 136 which leads to the fuel nozzle to bedescribed. Passage135 leads out from outlet port 137 providedLinf/sleeve130.

Levers-124 and 125 are provided with slots 144 and 145, respectively,through which pass studs 146 andl 147, respectively, carried by fulcrumplate 148. Plate 148 is provided with a slot 149 through which projectsa stud 150 mounted upon a wall of crank case 31. A spacing washer 151 islocated between l attached by means of stud 153 a bell-crank lever 154which is rotatably supported upon The cycle of operations of the pump isshown by Figs. 7, 9,10 and 11. In Fig. 7, the plungers 128 and 129are'located in touching relation opposite the fuel inlet part 134.Turning cam' 43 in the direction of the arrow 155-causes the plungersfirst to be separated,

as shown in Fig. 9, causing fuel to be sucked into sleeve 130. Furtherturning of cam 43 causes plungers 128 and 129 to move equal distances tothe respective positions shown in Fig. 10 which are opposite outlet port137. Further turning of cam 43 causes plungers 128 and 129 to cometogether as shown in Fig. 11, thereby causing the fuel tobe'force'd outthrough pipe 136. When a revolution of cam 43 has been completed thepump plun ers will be returned to the respective positions shown in Fig.7. The pump cam 43 is timed so that fuel will begin to be ejectedthrough Ilpipe 136 at the end of the compres'- sion stro e.

The speed of the engine is controll by.

moving lever 154 so as to raise or lower the fulcrum studs 146 and147.If studs 146 and 147 be moved to the upper-most position much less fuelwill be pumped from the fuel tank and ejected into pipe 136. With thefulcrum studs in such a position, the operation will be as illustratedin Figs. 12,13,14 and 15 showing positions of the plungerscorrespondingfto Figs. 7, 9, 10 and 11 respectively. It will beobservedin Fig.V 13 that the plungers are retracted to a lesser extentthan in Fig. 9. Therefore a smaller amount of fuel is sucked into thepump and ejected when the plungers come together again as shown in Fig.15.

The fuel nozzle designated as a whole by numeral 160 will now bedescribed. Nozzle i 160 comprises casting 161 extending through *thecylinder wall and provided with a passage 162 connected with pipe 136.Passage 162 leads into passage 163` arranged axially of cylinder 33; andin passage 163 is loosely journalled a shaft 164, provided at each endwith a perforated disc 165.

Gears 42 and'46 mesh with gears 170 and 171 respectively, carried byshaft 172 which is lrotatably mounted upon frame30 and carries a drivingpulley 173. Pulley 173 may be provided with a crank 174 for starting theengine.

The operation of the engine is as follows:

Air for `combustion and scavenging purposes is drawn during thecompression stroke, through ports 111 and 112 into-the crank cases 31and 32. During the operation of the-engine, the fan 50 draws air inthrough passages 84 and blows it out through air intake pipe 90 and intoannular passage 91 where it is substantially compressed. .This airenters thecylinder 33 at a time to be described later and is caused toswirl by reason of the tangential relation of pipe 90 to the passage 91.The swirling airis moved toward 89 nozzle 16() during the compressionstroke and causes discs 165 to rotate.

At low speed valve ports 111, 112 are closed during the expansionstrokewof the pistons and whatever air enters the cylinder aft@`pistons. Hence, the partial vacuum which it creates due to sucking airthrough the crank cases lfaster than the pistons could ump it, wouldcreate a suflicient vacuum to eep the valve'po'rts 111, 112 openconstantly.

At the end of the-compression stroke fuel is ejected through nozzle 160and spreads out over the surfaces of the discs 165 and fills theperforations. Thgrswirlingvairwas/itepasses through the perforated discspicks up the fuel i i drops and causes them to bewhirled around togetherwith the fuel mist which is thrown off the edges of the .rotating discs.In this manner an intimate mixture of fuel and combustion air is rapidlysecured.

The -fuel is preferably ignited by theheat of com ression. Thecombustion space is prefera ly one-twelfth the displacement 'spacesothat the air will be raised to a temperaturesuflicient for fuelignition purposes by compressing it within the cylinder.

During a portion of the' combustion stroke the fuel continues to burn,and to develop power for driving the pistons. The fuel pump is operatedso that the maximum amount of fuel injectedis sufficient to consumesubstantially all of the combustion air when the engine operates at fullload. The engine speed is decreased by adjusting the lever 154 so thatless-fuel will beinjected.

As the pistonsgland 35 are drivenv outwardly, from positions shown inFig. 2 to positions shown in Fig. 3, this movement being-indicated byarrows 34A and 35A, the exhaust ports 71 will be uncovered before thepiston uncovers ports 93. The swirling products of combustion will passout ports 71 into passage 70 in the manner indicated by arrows 71a inFig. 18. The exhaust will beging to expand as it passes through pipe 64v to the turbine chamber 54 and will attain a velocity suiicient todrive the turbine rotor 45. Some of the energy of the exhaust will begiven up to the rotor to assist in driving the engine. The passing ofthe exhaust through the rotor and the dividing of it by ledge 56 intotwo streamswhich meet against the ledge 57 is effective in deflectingthe rush of the exhaust into the atmosphere and thereby retarding itsflow.

By the time piston 34 has moved to outer dead-center position (see Fig.4), piston 35 will have completely uncovered ports 93 in valve 92,permitting the initially compressed air in the chamber 91 to. rush inand blow out the dead air. at the end of the cylinder where nearestpiston 35.

As the rotation of shafts 38 and 41 continues in the direction of arrows38A and 11A` respectively, the pistons 34 and 35 move in direction ofarrows 34B and 35B respectively. While exhaust vports 71 are beingcovered by the piston 34, valve 92 isv being moved to vopen position bycams 47 and 48, so that by theA time ports 71 are fully covered, valve92 is in full open position as shown vce in Fig. 5. Before ports 71 areclosed, fresh air, which has been initially compressed by the outwardmovement of the pistons or the centrifugal blower depending on the speedof the motor, will swirl through the cylinder and completely driveoutthe exhaust? fTlis fresh air by its whirling 'motion/tends tomaintain its own plane of rotation, and, therefore, the mixing of thefresh air with the dead air will be reduced to a minimum.

After ports 71 are closed, the slidevalve 9.2- remains open, permittingadditional fresh air to pile up whatever. pressure the blower maygenerate.

In an ordinary two-cycle engine the intake -port would' have been openedsoonerthan in the present invention, thereby allowing less time for thepressure of the exhaust to drop low enough vfor fresh air to enter. Inan ordinary two-cycle engine, the intake port would also have beenclosed before the exhaust port closed, thereby allowing less time forfresh air to enter to drive. out the exhaust, than vis the case of thepresent invention. Therefore, the present invention is adapted to beoperated at a much higher speed thanthe ordinary two-cycle engine.

A further'advantage of he present invention over the ordinary two-cycleengine is that the pistons displace a volume of air in the crank casesequal to a very large percent of .the total crankvcaseand cylindervolume.

lhe result is that the pistons themselves raise the pressure of the airhigher than in the case of the ordinary two-cycle engine where the-ratioof piston displacement to crank case volume is relatively small.

After piston 35 closes off communication between passage 91 and cylinder33, valve 92 begins moving to closed position which it reached by thetime piston 35 has reached inner dead-center position.

When the pistons 34 and 35 have reached the inner deadfcenter positionsshown in Fig. 2, fuel is aga-in injected and burned, and the cycle ofoperations whch has been described is repeated. v i

During the burning of the fuel the mixing of the burnt air with freshair is reduced to a minimum in the present invention. The

fresh air is caused to whirl as it enters theV cylinder by meanshereinbefore described. As this air is compressed it is still whirlingand the fuel nozzle discs 165 take up thismotion. By the time thepistons reach .the inner dead-center the air is still whirling thoughretarded by the fuel nozzle stem and by friction of the air itself.

However, the discs 165 have stored some energy during the rst part ofthe compression stroke and give up this energy to the air during thelatter part of the compression stroke tending to maintain the whirlingmotion. With the pistons located at inner deadcenter, most of thecompressed air is confined betweenthe discs 165. -As the 34 and35'separate, the air expands t rough and around the discs carrying thefuel Oil with it, which burns as it is ejected from the nozzle and mixeswith the air. The air supporting combustion has still enough whirlingmotion to maintain itself in its own plane of rotation, and, therefore,the burnt air does not tend to mix with the fresh air which is pushingoutwardly from the center point of the cylinder toward the outer endsthereof.

Vibration is substantially eliminated by providingin the one cylinder,two pistons of equal weight which drive two crank shafts istons lot inopposite directions through connecting rods and cranks of equal weight;and b providing that the two shafts together witl the respective partsrotating therewith shall develop equal kinetic energies. Since there isonly one slide valve 92, the oscillating counterbalances 101 and 102 areprovided to eliminate vibration. A By eliminating vibration, the extentof use of the engine is greatly increased. It can be operated without aheavy foundation and therefore may be readily transported while inoperation. It can therefore be constructed as a portable power devicefor all sorts of purposes, including domestic use and use as the primemover of a portable hand tool such as a drill, saw or planer.

The portability of the en'ne is further increased by the use of smallywheels which lll' develop the same energy of rotation as theconventional large'flywheel directly connected to the crank shaft.

The gearing up of the flywheels is taken advantage of by constructingthe flywheels so that one may act as a high-speed fan rotor, and theother may serve as a turbine rotor converting some of the energy of theexhaust into useful power, and, at the same time, serving as one elementof an exhaust muiiler.

It is to be understood that the invention is not restricted to theparticular impulse tur-- bine disclosed, but that any other conventionaltype may be used.

It is to be understood that some form of cooling system is used forcooling the cylinder and fuel nozzle. For sake of clearness, the coolingsystem has been omitted from the drawings.

While the form of mechanism herein shown i and described constitutes apreferred form of embodiment of the invention, it is to be understoodthat other forms mightbe adopted, all coming within the scope of theclaims which follow.

The present application is a divisional application of my formerapplication led on the v13th day of December, 1919, Ser. No. 344,715;

What I claim is as follows: i

1. In an internal combustion engine, the combination with a cylinderhaving an air intake passage, of a rotary air compressor connected withthe intake passage, including a'rotor serving as an engine flywheel ofrelatively small mass, a pair of oppositely reciprocating pistons in thecylinder, a pair of shafts, mechanical connections between the pistonsand the shafts for rotating the latter -in opposite directions, a secondflywheel, and

high speed gearing between one shaft and said flywheel and between theother shaft and said compressor rotor for effecting the re'- lativelyrapid rotation of said flywheel elements in opposite directions therebyobtaining a dynamic balance, said air compressor and said secondflywheel serving conjointlyr as the major influence in obtaining saiddynamic balance.

2. In an internal combustion engine, the combination with a cylinderhaving an eX- haust passage, of apturbine connected with the exhaustpassage, said turbine including a. rotor serving as an engine flywheelof relatively small mass, a pair of oppositely reciprocating'pistons inthe cylinder, a pair of shafts, mechanical connections between thepistons and the shafts for rotating the latter in opposite directions, asecond ilywheeh'and high speed gearing between one shaft and saidiywheel and between the other shaft and said turbine rotor for effectingthe relatively rapid rotation of said flywheel elements in oppositedirections, thereby obtaining a dynamic balance, said turbine and saidsecond flywheel serving conj'ointly to set up the principal influenceinthe obtaining of said balance.

3. In an internal combustion engine, the combination with a cylinderhaving'intake and exhaust passages, of a rotary air compressor connectedwith the intake passage, including a rotor serving as an engine-flywheel of relatively small mass, a turbine connected with the exhaustpassage, said turbine including a rotor serving as an engine flywheel ofrelatively small massfa pair of oppositely reciprocating pistons in thecylinder,

a pair of shafts, mechanical connections between the pistons and theshafts for rotating the latter in opposite directions, and high speedgearing between one shaft and said compressor rotor, and between theother shaft and the turbine rotor for effecting the relatively rapidrotation of said ywheel elements in opposite directions.

In testimony whereof I affix my signature.

' WILLIAM H. ROBERTSON.

